Contaminated and Hazardous
Waste Site Management
Not biotic; not formed by biologic processes.
Viscosity: A measure of a fluid's resistance to tangential or shear stress. Also
referred to as dynamic viscosity; see also viscosity. Units are usually given
Absorbance: A measure of the decrease in incident
light passing through a sample into the detector. It is defined mathematically
as: I = radiation intensity
Absorption: The penetration of atoms, ions,
or molecules into the bulk mass of a substance.
Accoustic impedence: Reflects
the ability of a boundary to reflect seismic energy. It is the contrast of density
times velocity across the boundary. A measure of the seismic inertia of the medium.
Refers to closeness of a measurement to the true value.
of numerous, generally filamentous, and often pathogenic, microorganisms resembling
both bacteria and fungi.
Action Level: The concentration of a contaminant
above which some action (monitoring, clean up, etc.) is required by regulation.
Layer/Zone: In permafrost terrains, the zone that undergoes cycles of freezing
Adsorption: The retention of atoms, ions, or molecules onto
the surface of another substance.
Advection: Process by which a solute is
transported in groundwater, and moves at the same velocity.
process of bringing air into contact with a liquid (typically water), usually
by bubbling air through the liquid, spraying the liquid into the air, allowing
the liquid to cascade down a waterfall, or by mechanical agitation. Aeration serves
to (1) strip dissolved gases from solution, and/or (2) oxygenate the liquid. The
rate at which a gas transfers into solution can be described by Fick's First Law.
Refers to any process carried out in the presence of oxygen.
An off-gas post-treatment unit for control of organic compounds by thermal oxidation.
A typical afterburner is a refractory-lined shell providing enough residence time
at a sufficiently high temperature to destroy organic compounds in the off-gas
Aggregate: Coarse mineral material (e.g., sand, gravel) that is
mixed with either cement to form concrete or tarry hydrocarbons to form asphalt.
Table: The surface between the vadose zone and the oil; pressure of oil in the
porous medium is equal to atmospheric pressure.
Air Stripping: A treatment
system that removes, or "strips," volatile organic compounds from contaminated
groundwater or surface water by forcing an airstream through the water and causing
the compounds to evaporate.
Algae: Chiefly aquatic, eucaryotic one-celled
or multicellular plants without true stems, roots and leaves, that are typically
autotrophic, photosynthetic, and contain chlorophyll. Algae are not
found in groundwater.
Aliphatic: Of or pertaining to a broad category of
carbon compounds distinguished by a straight, or branched, open chain arrangement
of the constituent carbon atoms. The carbon-carbon bonds may be either saturated
or unsaturated. Alkanes, alkenes, and alkynes are aliphatic hydrocarbons.
A measured portion of a sample taken for analysis. One or more aliquots make up
Alkanes: The homologous group of linear saturated aliphatic hydrocarbons
having the general formula CnH2n+2. Alkanes can be straight chains, branched chains,
or ring structures. Also referred to as paraffins.
Alkenes: The group of
unsaturated hydrocarbons having the general formula CnH2n and characterized by
being highly chemically reactive. Also referred to as olefins.
The group of unsaturated hydrocarbons with a triple Carbon-Carbon bond having
the general formula CnH2n-2.
Alluvial Deposits: The general name for all
sediments, including clay, (Alluvium) silt, sand, gravel or similar unconsolidated
material deposited in a sorted or semi-sorted condition by a stream or other body
of running water, in a stream bed, floodplain, delta or at the base of a mountain
slope as a fan.
Alluvial Fans: A fan shaped deposit of detrital material
deposited by a stream where it emerges from a steep mountain slope or from an
upland onto a less steeply sloping terrain.
Alluvium: A general term for
unconsolidated material (e.g. clay, silt, sand, gravel) deposited from running
water. Often a sorted or semi-sorted sediment in the bed of a stream or on its
floodplain or delta. The deposit may be in the form of an alluvial fan.
Ambient Groundwater Flow: The rate of flow and direction of
flow of groundwater under unpumped, natural conditions.
maximum departure of a wave from the average value.
Anaerobic: In the absence
Analog: In chemistry, a structural derivative of a parent compound.
Date/Time: The date and military time of the injection of the sample, standard,
or blank into the GC/MS or GC system.
Analyte: The element or ion an analysis
seeks to determine; the element of interest.
Analytical Sample: Any solution
or media introduced into an instrument on which an analysis is performed excluding
instrument calibration, initial calibration verification, initial calibration
blank, continuing calibration verification and continuing calibration blank. Note
the following are all defined as analytical samples: undiluted and diluted samples
(EPA and non-EPA), predigestion spike samples, duplicate samples, serial dilution
samples, analytical spike samples, post-digestion spike samples, interference
check samples (ICS), CRDL standard for AA (CRA), CRDL standard for ICP (CRI),
laboratory control sample (LCS), preparation blank (PB) and linear range analysis
Analytical Spike: The furnace post-digestion spike. The addition
of a known amount of standard after digestion.
Anion: A negatively charged
atom or radical.
Anisotropic: The condition in which hydraulic properties
of an aquifer are not equal when measured in all directions.
The conditions under which one or more of the hydraulic properties of an aquifer
vary with direction.
Annulus: The space between well casing or screen and
the borehole wall, or between drill pipe and casing, or between separate sets
Anomaly: Refers to deviation from uniformity in a physical property.
Resistivity/Conductivity: The resistivity of a homogeneous isotropic ground that
would give the same voltage/current or secondary/primary field ratios as observed
in the field with resistivity or EM methods. The apparent conductivity is the
reciprocal of the apparent resistivity.
Aqueous solubility: The extent to
which a compound will dissolve in water. The log of solubility is generally inversely
related to molecular weight.
Aquiclude: An outdated term for a geologic
layer of very low permeability located so that it forms an upper or lower boundary
to a groundwater flow system. Aquitard or Confining Layer are preferred terms.
Rocks or unconsolidated sediments that are capable of yielding a significant amount
of water to a well or a spring.
Aquifer Depletion: Aquifer depletion occurs
when groundwater is withdrawn from an aquifer at a rate greater than it can be
Aquifer Test: A test which involves adding to or discharging
from a well, measured quantities of water, and recording the resulting changes
in head in the aquifer (during and after addition/withdrawal). Examples are slug
tests, bail tests, and pumping tests.
Aquifer Vulnerability: A measure of
how vulnerable an aquifer is to contamination.
Aquifer Vulnerability Mapping:
Mapping the vulnerability of an aquifer to contamination from sources. Vulnerability
mapping does not consider the type of land use above an aquifer, only the intrinsic
vulnerability of the aquifer, typically based on the type, thickness, and extent
of geologic materials overlying an aquifer, depth to water, and type of aquifer
Aquitard: A geologic formation that may contain groundwater
but is not capable of transmitting significant quantities of groundwater under
normal hydraulic gradients. In some situations aquitards may function as confining
Archie's Law: An empirical relationship linking formation resistivity
(rt), formation water resistivity (rw) and porosity q. The form of the relationship
is: rt = arwq-m where a and m are experimentally determined constants.
Of or relating to organic compounds that resemble benzene in chemical behavior.
These compounds are unsaturated and characterized by containing at least one 6-carbon
Artesian: The condition of water in a confined aquifer being
under sufficient pressure that the potentiometric surface is above the bottom
of the overlying confining bed. Water levels within wells screened in an artesian
aquifer rise to a point above the bottom of the confining bed that overlies the
aquifer (it is not necessary for the water to flow at land surface). If the water
is under enough pressure so that the potentiometric surface is above land surface,
water may actually flow from the well without pumping. Such a well is a flowing
Asymptote: A line that is considered to be the limit to
a curve. As the curve approaches the asymptote, the distance separating the curve
and the asymptote continues to decrease, but the curve never actually intersects
Attenuation, Attenuate: The reduction or removal of groundwater
constituents by the sum of all physical, chemical, and biological factors acting
upon the groundwater. In geophysical terms, it refers to a reduction in energy
or amplitude caused by the physical characteristics of a transmitting system.
Limits: The moisture contents which define a soil's liquid limit, plastic limit,
and sticky limit.
Auger: A tool for drilling/boring into unconsolidated
earth materials (soil) consisting of a spiral blade wound around a central stem
or shaft that is commonly hollow (hollow-stem auger). Augers commonly are available
in flights (sections) that are connected together to advance the depth of the
Auger Flights: Winding metal strips welded to auger sections.
They carry cuttings to the surface during drilling.
The temperature at which a substance will spontaneously ignite. Autoignition temperature
is an indicator of thermal stability for petroleum hydrocarbons.
Designating or typical of organisms that derive carbon for the manufacture of
cell mass from inorganic carbon (carbon dioxide).
Autozero: Zeroing the
instrument at the proper wavelength. It is equivalent to running a standard blank
with the absorbance set at zero.
Average Linear Groundwater Velocity: The
velocity of groundwater moving through porous rock or sediment. It is the time
required for the water to move from A to B divided by the linear distance from
A to B.